<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css"
        integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">

    <style>
      
         .container{
            width: 500px;
           
            background-color:salmon;
        } 
    </style>

</head>

<body>
    <div class="container">
    <form>
        <div class="form-group">
          <label for="InputEmail1">Email address</label>
          <input type="email" class="form-control" id="exampleInputEmail1" placeholder="Email">
        </div>

        <div class="form-group">
          <label for="exampleInputPassword1">Password</label>
          <input type="password" class="form-control" id="exampleInputPassword1" placeholder="Password">
        </div>

        <div class="form-group">
          <label for="exampleInputFile">File input</label>
          <input type="file" id="exampleInputFile">
          <p class="help-block">Example block-</p>
        </div>

        <div class="checkbox">
          <label>
            <input type="checkbox"> Check me out
          </label>
        </div>
        
        <button type="submit" class="btn btn-default">Submit</button>
      </form>
    </div>
</body>